import java.util.HashMap;
import java.util.Map;
public class BookManager {
    static class Book {
        String id;
        String title;
        String author;
        public Book(String id, String title, String author) {
            this.id = id;
            this.title = title;
            this.author = author;
        }
        @Override
        public String toString() {
            return "Book{" +
                    "id='" + id + '\'' +
                    ", title='" + title + '\'' +
                    ", author='" + author + '\'' +
                    '}';
        }
    }
    public static void updateBook(Book book, String fieldMask) {
        String[] fieldsToUpdate = fieldMask.split(",");
        Map<String, String> updates = new HashMap<>();
        for (String field : fieldsToUpdate) {
            String[] keyValue = field.split("=");
            if (keyValue.length == 2) {
                updates.put(keyValue[0].trim(), keyValue[1].trim());
            }
        }
        if (updates.containsKey("title")) {
            book.title = updates.get("title");
        }
        if (updates.containsKey("author")) {
            book.author = updates.get("author");
        }
    }
    public static void main(String[] args) {
        Book book = new Book("1", "Old Title", "Old Author");
        System.out.println("Before update: " + book);
        updateBook(book, "title=New Title, author=New Author");
        System.out.println("After update: " + book);
    }
}

请编写一个Java程序，实现一个简单的图书管理系统中的图书更新功能。在这个系统中，每本图书都有一个唯一的ID、书名和作者名。你需要实现一个方法，该方法接受一个图书对象和一个更新掩码（FieldMask），然后根据更新掩码指定的字段来更新图书信息。更新掩码是一个字符串，包含需要更新的字段名，字段名之间用逗号分隔。如果更新掩码为空，则不更新任何字段。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.HashMap;
import java.util.Map;
public class BookManager {
    static class Book {
        String id;
        String title;
        String author;
        public Book(String id, String title, String author) {
        }
        @Override
        public String toString() {
            return "Book{" +
                    "id='" + id + '\'' +
                    ", title='" + title + '\'' +
                    ", author='" + author + '\'' +
                    '}';
        }
    }
    public static void updateBook(Book book, String fieldMask) {
    }
}
```

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
public class BookManagerTest {
    @Test
    public void testUpdateTitleAndAuthor() {
        BookManager.Book book = new BookManager.Book("1", "Old Title", "Old Author");
        BookManager.updateBook(book, "title=New Title, author=New Author");
        assertEquals("New Title", book.title);
        assertEquals("New Author", book.author);
    }
    @Test
    public void testUpdateTitleOnly() {
        BookManager.Book book = new BookManager.Book("1", "Old Title", "Old Author");
        BookManager.updateBook(book, "title=New Title");
        assertEquals("New Title", book.title);
        assertEquals("Old Author", book.author);
    }
    @Test
    public void testUpdateAuthorOnly() {
        BookManager.Book book = new BookManager.Book("1", "Old Title", "Old Author");
        BookManager.updateBook(book, "author=New Author");
        assertEquals("Old Title", book.title);
        assertEquals("New Author", book.author);
    }
    @Test
    public void testUpdateNoChanges() {
        BookManager.Book book = new BookManager.Book("1", "Old Title", "Old Author");
        BookManager.updateBook(book, "");
        assertEquals("Old Title", book.title);
        assertEquals("Old Author", book.author);
    }
    @Test
    public void testUpdateWithInvalidMask() {
        BookManager.Book book = new BookManager.Book("1", "Old Title", "Old Author");
        BookManager.updateBook(book, "title=New Title, invalidField=invalid");
        assertEquals("New Title", book.title);
        assertEquals("Old Author", book.author);
    }
}


import java.util.Scanner;
public class RightAlignedTriangle {
    public static String generatePattern(int height) {
        StringBuilder pattern = new StringBuilder();
        for (int row = 0; row < height; row++) {
            for (int space = 0; space < height - row - 1; space++) {
                pattern.append(" ");
            }
            for (int star = 0; star <= row; star++) {
                pattern.append("*");
            }
            pattern.append(System.lineSeparator());
        }
        return pattern.toString();
    }
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入三角形的高度：");
        int height = scanner.nextInt();
        String trianglePattern = generatePattern(height);
        System.out.println(trianglePattern);
    }
    public static boolean checkPattern(int height, String expectedPattern) {
        String generatedPattern = generatePattern(height);
        return generatedPattern.equals(expectedPattern);
    }
}

请编写一个Java程序，用于生成一个右对齐的三角形图案。该三角形的高度由用户输入决定，每一行的图案由字符`*`组成，且每一行的字符数量逐渐增加。例如，如果用户输入高度为4，那么输出的图案应该如下所示：

```
   *
  **
 ***
****
```

请确保你的程序满足以下要求：
- 使用Java编程语言。
- 程序中包含一个名为`RightAlignedTriangle`的类和一个名为`generatePattern`的方法。
- `generatePattern`方法接收一个整型参数`height`，表示三角形的高度，并返回一个字符串，该字符串包含了整个三角形图案。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.Scanner;
public class RightAlignedTriangle {
    public static String generatePattern(int height) {
    }
    public static boolean checkPattern(int height, String expectedPattern) {
    }
}
```

Question: Write a piece of python code to achieve the following function.
Find the maximum perfect square number that is less than the nth Fibonacci number.
The function's name is max_square_number, and the input is an integer n.

Answer:
```python
def max_square_number(n):
 if n <= 2:
 return 0 # For the first two numbers in the Fibonacci sequence, no complete square numbers can be used.

 fibs = [0, 1] # Store the first two numbers of the Fibonacci sequence
 squares = [] # Store the list of perfect square numbers

 max_square = 0
 i = 2

 while i <= n:
 fibs.append(fibs[i-1] + fibs[i-2]) # Calculate the next Fibonacci number
 i += 1

 fib = fibs[-1]
 perfect_squares = [i**2 for i in range(1, int(math.sqrt(fib)) + 1)]
 max_square = max(filter(lambda x: x < fib, perfect_squares))
 return max_square
```

----------------

import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.api.Test;
public class RightAlignedTriangleTest {
    @Test
    void generatePattern_heightZero_shouldReturnEmptyString() {
        int height = 0;
        String expectedPattern = "";
        String actualPattern = RightAlignedTriangle.generatePattern(height);
        assertEquals(expectedPattern, actualPattern);
    }
    @Test
    void generatePattern_heightOne_shouldReturnSingleAsterisk() {
        int height = 1;
        String expectedPattern = "*\n";
        String actualPattern = RightAlignedTriangle.generatePattern(height);
        assertEquals(expectedPattern, actualPattern);
    }
    @Test
    void generatePattern_heightThree_shouldReturnTriangle() {
        int height = 3;
        String expectedPattern = "  *\n **\n***\n";
        String actualPattern = RightAlignedTriangle.generatePattern(height);
        assertEquals(expectedPattern, actualPattern);
    }
    @Test
    void checkPattern_correctPattern_shouldReturnTrue() {
        int height = 3;
        String expectedPattern = "  *\n **\n***\n";
        assertTrue(RightAlignedTriangle.checkPattern(height, expectedPattern));
    }
    @Test
    void checkPattern_incorrectPattern_shouldReturnFalse() {
        int height = 3;
        String incorrectPattern = "  *\n **\n*** \n";
        assertFalse(RightAlignedTriangle.checkPattern(height, incorrectPattern));
    }
}


import java.util.Arrays;
class Book {
    boolean isBorrowed;
    public Book(boolean isBorrowed) {
        this.isBorrowed = isBorrowed;
    }
    public void setBorrowed(boolean isBorrowed) {
        this.isBorrowed = isBorrowed;
    }
    public boolean isBorrowed() {
        return this.isBorrowed;
    }
}
class Library {
    Book[] books;
    public Library(Book[] books) {
        this.books = books;
    }
    public void resetBooksStatus() {
        for (Book book : books) {
            book.setBorrowed(false);
        }
    }
}
public class Main {
    public static void main(String[] args) {
        Book[] books = {
            new Book(true),
            new Book(false),
            new Book(true),
            new Book(true)
        };
        Library library = new Library(books);
        library.resetBooksStatus();
        check(books);
    }
    public static void check(Book[] books) {
        for (Book book : books) {
            if (book.isBorrowed()) {
                System.out.println("错误：存在未正确重置的图书。");
                return;
            }
        }
        System.out.println("所有图书的状态已正确重置为未借出。");
    }
}

请编写一个Java程序，实现一个简单的图书管理系统中的一个功能：重置所有图书的状态为未借出。在这个系统中，每本图书都有一个状态，表示该图书是否被借出。我们使用一个`Book`类来表示每本图书，其中包含一个布尔类型的成员变量`isBorrowed`，表示图书的借出状态（`true`表示已借出，`false`表示未借出）。你需要编写一个名为`Library`的类，其中包含一个方法`resetBooksStatus`，该方法将库存中所有图书的状态重置为未借出。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.Arrays;
class Book {
    boolean isBorrowed;
    public Book(boolean isBorrowed) {
    }
    public void setBorrowed(boolean isBorrowed) {
    }
    public boolean isBorrowed() {
    }
}
class Library {
    Book[] books;
    public Library(Book[] books) {
    }
    public void resetBooksStatus() {
    }
}
```

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
class BookTest {
    @Test
    public void testSetBorrowed() {
        Book book = new Book(false);
        book.setBorrowed(true);
        Assertions.assertTrue(book.isBorrowed());
    }
    @Test
    public void testIsBorrowed() {
        Book book = new Book(true);
        Assertions.assertTrue(book.isBorrowed());
    }
    @Test
    public void testConstructor() {
        Book book = new Book(false);
        Assertions.assertFalse(book.isBorrowed());
    }
}
class LibraryTest {
    @Test
    public void testResetBooksStatus() {
        Book[] books = {
            new Book(true),
            new Book(true),
            new Book(true)
        };
        Library library = new Library(books);
        library.resetBooksStatus();
        for (Book book : books) {
            Assertions.assertFalse(book.isBorrowed());
        }
    }
    @Test
    public void testResetBooksStatusWithMixedStatus() {
        Book[] books = {
            new Book(true),
            new Book(false),
            new Book(true),
            new Book(false)
        };
        Library library = new Library(books);
        library.resetBooksStatus();
        for (Book book : books) {
            Assertions.assertFalse(book.isBorrowed());
        }
    }
}


import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Random;
public class SongSelector {
    private HashMap<String, List<String>> genreToSongsMap;
    private Random random;
    public SongSelector() {
        genreToSongsMap = new HashMap<>();
        random = new Random();
    }
    public void addSong(String genre, String song) {
        genreToSongsMap.computeIfAbsent(genre, k -> new ArrayList<>()).add(song);
    }
    public String getRandomSongFromGenre(String genre) {
        List<String> songs = genreToSongsMap.get(genre);
        if (songs == null || songs.isEmpty()) {
            return null;
        }
        int index = random.nextInt(songs.size());
        return songs.get(index);
    }
    public static void main(String[] args) {
        SongSelector selector = new SongSelector();
        selector.addSong("Pop", "Song A");
        selector.addSong("Pop", "Song B");
        selector.addSong("Rock", "Song C");
        System.out.println("Random Pop Song: " + selector.getRandomSongFromGenre("Pop"));
        System.out.println("Random Rock Song: " + selector.getRandomSongFromGenre("Rock"));
        System.out.println("Random Jazz Song: " + selector.getRandomSongFromGenre("Jazz"));
    }
}

假设你正在开发一个音乐播放器应用，你需要实现一个功能，从给定的歌曲集合中随机选择一首歌曲进行播放。每首歌曲都属于一个特定的流派（如流行、摇滚、爵士等），用户可以选择一个流派，然后应用会从该流派中随机选择一首歌曲播放。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Random;
public class SongSelector {
    private HashMap<String, List<String>> genreToSongsMap;
    private Random random;
    public SongSelector() {
    }
    public void addSong(String genre, String song) {
    }
    public String getRandomSongFromGenre(String genre) {
    }
}
```

import org.junit.Before;
import org.junit.Test;
import static org.junit.Assert.*;
public class SongSelectorTest {
    private SongSelector songSelector;
    @Before
    public void setUp() {
        songSelector = new SongSelector();
    }
    @Test
    public void testAddSong() {
        songSelector.addSong("Pop", "Song A");
        String song = songSelector.getRandomSongFromGenre("Pop");
        assertNotNull(song);
    }
    @Test
    public void testGetRandomSongFromGenreWithSingleSong() {
        songSelector.addSong("Rock", "Song C");
        String song = songSelector.getRandomSongFromGenre("Rock");
        assertEquals("Song C", song);
    }
    @Test
    public void testGetRandomSongFromGenreWithMultipleSongs() {
        songSelector.addSong("Pop", "Song A");
        songSelector.addSong("Pop", "Song B");
        String song = songSelector.getRandomSongFromGenre("Pop");
        assertTrue(song.equals("Song A") || song.equals("Song B"));
    }
    @Test
    public void testGetRandomSongFromGenreWithNoSongs() {
        String song = songSelector.getRandomSongFromGenre("Jazz");
        assertNull(song);
    }
    @Test
    public void testGetRandomSongFromEmptyGenre() {
        songSelector.addSong("Classical", "Song D");
        songSelector.getRandomSongFromGenre("Classical");
        String song = songSelector.getRandomSongFromGenre("EmptyGenre");
        assertNull(song);
    }
}


import java.util.ArrayList;
import java.util.List;
public class DataNotifier {
    private List<Object> dataList;
    private List<Object> initDataList() {
        return new ArrayList<>();
    }
    public void addElementsAndNotify(List<Object> newElements) {
        if (dataList == null) {
            dataList = initDataList();
        }
        if (newElements == null) {
            newElements = new ArrayList<>();
        }
        if (newElements.isEmpty()) {
            return;
        }
        dataList.addAll(newElements);
        notifyDataChanged();
    }
    private void notifyDataChanged() {
        System.out.println("数据已更改。");
    }
    public static void main(String[] args) {
        DataNotifier notifier = new DataNotifier();
        List<Object> elementsToAdd = new ArrayList<>();
        elementsToAdd.add("Java");
        elementsToAdd.add("Python");
        notifier.addElementsAndNotify(elementsToAdd);
        notifier.addElementsAndNotify(null);
        List<Object> emptyList = new ArrayList<>();
        notifier.addElementsAndNotify(emptyList);
    }
}

请编写一个Java方法，用于向自定义的数据集合中添加一系列元素，并在添加后通知数据已更改。该方法应满足以下要求：

1. 如果传入的集合为`null`，则应创建一个新的空集合。
2. 如果传入的集合为空，则不执行任何操作。
3. 在添加元素后，应调用一个方法来通知数据已更改。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.ArrayList;
import java.util.List;
public class DataNotifier {
    private List<Object> dataList;
    private List<Object> initDataList() {
    }
    public void addElementsAndNotify(List<Object> newElements) {
    }
    private void notifyDataChanged() {
    }
}
```

import org.junit.Test;
import org.junit.Before;
import java.util.ArrayList;
import java.util.List;
import static org.junit.Assert.*;
public class DataNotifierTest {
    private DataNotifier dataNotifier;
    @Before
    public void setUp() {
        dataNotifier = new DataNotifier();
    }
    @Test
    public void testAddElementsAndNotify_WithNonNullElements() {
        List<Object> elementsToAdd = new ArrayList<>();
        elementsToAdd.add("Java");
        elementsToAdd.add("Python");
        dataNotifier.addElementsAndNotify(elementsToAdd);
    }
    @Test
    public void testAddElementsAndNotify_WithNullElements() {
        dataNotifier.addElementsAndNotify(null);
    }
    @Test
    public void testAddElementsAndNotify_WithEmptyList() {
        List<Object> emptyList = new ArrayList<>();
        dataNotifier.addElementsAndNotify(emptyList);
    }
    @Test
    public void testAddElementsAndNotify_NoPriorInitialization() {
        List<Object> elementsToAdd = new ArrayList<>();
        elementsToAdd.add("Java");
        elementsToAdd.add("Python");
        dataNotifier.addElementsAndNotify(elementsToAdd);
    }
    @Test
    public void testAddElementsAndNotify_MultipleCalls() {
        List<Object> firstBatch = new ArrayList<>();
        firstBatch.add("Java");
        List<Object> secondBatch = new ArrayList<>();
        secondBatch.add("Python");
        dataNotifier.addElementsAndNotify(firstBatch);
        dataNotifier.addElementsAndNotify(secondBatch);
    }
}


import java.util.HashMap;
import java.util.Map;
public class BookLoanManager {
    private Map<Long, Long> bookBorrowTimes;
    public BookLoanManager() {
        bookBorrowTimes = new HashMap<>();
    }
    public void setBorrowTime(Long bookId, Long borrowTime) {
        bookBorrowTimes.put(bookId, borrowTime);
    }
    public Long getLastBorrowedTime(Long bookId) {
        return bookBorrowTimes.getOrDefault(bookId, null);
    }
    public static void main(String[] args) {
        BookLoanManager manager = new BookLoanManager();
        manager.setBorrowTime(1001L, 1625140800000L);
        manager.setBorrowTime(1002L, 1625227200000L);
        check(manager.getLastBorrowedTime(1001L) == 1625140800000L, "书籍1001的借阅时间检查失败");
        check(manager.getLastBorrowedTime(1002L) == 1625227200000L, "书籍1002的借阅时间检查失败");
        check(manager.getLastBorrowedTime(1003L) == null, "书籍1003的借阅时间检查失败");
    }
    private static void check(boolean condition, String message) {
        if (!condition) {
            throw new AssertionError(message);
        }
    }
}

请编写一个Java程序，用于管理图书馆中书籍的借阅信息。具体来说，需要实现一个方法，该方法接收一个书籍ID作为参数，并返回该书籍的最后借阅时间。如果书籍未被借阅过，则返回null。确保代码片段包含所有必要的导入语句。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.HashMap;
import java.util.Map;
public class BookLoanManager {
    private Map<Long, Long> bookBorrowTimes;
    public BookLoanManager() {
    }
    public void setBorrowTime(Long bookId, Long borrowTime) {
    }
    public Long getLastBorrowedTime(Long bookId) {
    }
}
```

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
public class BookLoanManagerTest {
    private BookLoanManager manager;
    @BeforeEach
    public void setUp() {
        manager = new BookLoanManager();
    }
    @Test
    public void testSetAndGetBorrowTime() {
        manager.setBorrowTime(1001L, 1625140800000L);
        Long borrowTime = manager.getLastBorrowedTime(1001L);
        assertEquals(1625140800000L, borrowTime);
    }
    @Test
    public void testGetLastBorrowedTime_NotSet() {
        Long borrowTime = manager.getLastBorrowedTime(1003L);
        assertNull(borrowTime);
    }
    @Test
    public void testSetBorrowTime_Overwrite() {
        manager.setBorrowTime(1001L, 1625140800000L);
        manager.setBorrowTime(1001L, 1625301600000L);
        Long borrowTime = manager.getLastBorrowedTime(1001L);
        assertEquals(1625301600000L, borrowTime);
    }
    @Test
    public void testMultipleBooksBorrowTimes() {
        manager.setBorrowTime(1001L, 1625140800000L);
        manager.setBorrowTime(1002L, 1625227200000L);
        assertEquals(1625140800000L, manager.getLastBorrowedTime(1001L));
        assertEquals(1625227200000L, manager.getLastBorrowedTime(1002L));
    }
    @Test
    public void testGetLastBorrowedTime_WithBorrowTimeSetToNull() {
        manager.setBorrowTime(1004L, null);
        assertNull(manager.getLastBorrowedTime(1004L));
    }
}


import java.util.HashMap;
import java.util.Map;
public class WeekdayFinder {
    public static String getWeekdayName(int num) {
        Map<Integer, String> weekDays = new HashMap<>();
        weekDays.put(1, "星期一");
        weekDays.put(2, "星期二");
        weekDays.put(3, "星期三");
        weekDays.put(4, "星期四");
        weekDays.put(5, "星期五");
        weekDays.put(6, "星期六");
        weekDays.put(7, "星期日");
        return weekDays.getOrDefault(num, "无效输入");
    }
    public static void main(String[] args) {
        assert "星期一".equals(getWeekdayName(1));
        assert "星期二".equals(getWeekdayName(2));
        assert "星期三".equals(getWeekdayName(3));
        assert "星期四".equals(getWeekdayName(4));
        assert "星期五".equals(getWeekdayName(5));
        assert "星期六".equals(getWeekdayName(6));
        assert "星期日".equals(getWeekdayName(7));
        assert "无效输入".equals(getWeekdayName(8));
        assert "无效输入".equals(getWeekdayName(0));
        System.out.println("所有测试用例都通过了！");
    }
}

请编写一个Java方法，该方法接收一个整数参数`num`，并根据该参数的值返回对应的星期名称。如果`num`的值在1到7之间，分别返回“星期一”到“星期日”；如果`num`超出这个范围，返回“无效输入”。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.HashMap;
import java.util.Map;
public class WeekdayFinder {
    public static String getWeekdayName(int num) {
    }
}
```

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;
public class WeekdayFinderTest {
    @Test
    public void testWeekdayMonday() {
        assertEquals("星期一", WeekdayFinder.getWeekdayName(1));
    }
    @Test
    public void testWeekdayTuesday() {
        assertEquals("星期二", WeekdayFinder.getWeekdayName(2));
    }
    @Test
    public void testWeekdayWednesday() {
        assertEquals("星期三", WeekdayFinder.getWeekdayName(3));
    }
    @Test
    public void testWeekdaySaturday() {
        assertEquals("星期六", WeekdayFinder.getWeekdayName(6));
    }
    @Test
    public void testInvalidInput() {
        assertEquals("无效输入", WeekdayFinder.getWeekdayName(0));
    }
}


import java.io.File;
import java.io.FileNotFoundException;
public class DirectoryExplorer {
        public static void exploreDirectory(File directory) throws FileNotFoundException {
        if (!directory.exists()) {
            throw new FileNotFoundException("目录不存在: " + directory.getAbsolutePath());
        }
        File[] fileEntries = directory.listFiles();
        if (fileEntries != null) {
            for (File fileEntry : fileEntries) {
                if (fileEntry.isDirectory()) {
                    exploreDirectory(fileEntry);
                } else {
                    System.out.println(fileEntry.getName());
                }
            }
        }
    }
    public static void main(String[] args) {
        try {
            File startingDirectory = new File("path/to/start/directory");
            exploreDirectory(startingDirectory);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
}

请编写一个Java程序，该程序能够遍历指定目录下的所有文件和子目录，并打印出所有文件的名称。如果遇到子目录，则需要递归地遍历该子目录下的文件。确保程序能够正确处理空目录和不存在的目录。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.io.File;
import java.io.FileNotFoundException;
public class DirectoryExplorer {
        public static void exploreDirectory(File directory) throws FileNotFoundException {
    }
}
```

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertThrows;
import java.io.File;
import java.io.FileNotFoundException;
public class DirectoryExplorerTest {
    @Test
    public void testDirectoryNotExist() {
        File nonExistingDirectory = new File("non/existent/path");
        assertThrows(FileNotFoundException.class, () -> {
            DirectoryExplorer.exploreDirectory(nonExistingDirectory);
        });
    }
    @Test
    public void testEmptyDirectory() throws FileNotFoundException {
        File emptyDirectory = new File("path/to/empty/directory");
        if (!emptyDirectory.exists()) {
            emptyDirectory.mkdirs();
        }
        DirectoryExplorer.exploreDirectory(emptyDirectory);
    }
    @Test
    public void testDirectoryWithFiles() throws FileNotFoundException {
        File directoryWithFiles = new File("path/to/directory/with/files");
        if (!directoryWithFiles.exists()) {
            directoryWithFiles.mkdirs();
        }
        File file1 = new File(directoryWithFiles, "file1.txt");
        File file2 = new File(directoryWithFiles, "file2.txt");
        try {
            file1.createNewFile();
            file2.createNewFile();
        } catch (Exception e) {
            e.printStackTrace();
        }
        DirectoryExplorer.exploreDirectory(directoryWithFiles);
    }
    @Test
    public void testNestedDirectories() throws FileNotFoundException {
        File nestedDirectory = new File("path/to/nested/directory");
        if (!nestedDirectory.exists()) {
            nestedDirectory.mkdirs();
        }
        File subDirectory = new File(nestedDirectory, "subdirectory");
        if (!subDirectory.exists()) {
            subDirectory.mkdirs();
        }
        File file = new File(subDirectory, "file.txt");
        try {
            file.createNewFile();
        } catch (Exception e) {
            e.printStackTrace();
        }
        DirectoryExplorer.exploreDirectory(nestedDirectory);
    }
    @Test
    public void testDirectoryWithMixedContent() throws FileNotFoundException {
        File mixedDirectory = new File("path/to/mixed/content");
        if (!mixedDirectory.exists()) {
            mixedDirectory.mkdirs();
        }
        File subDirectory1 = new File(mixedDirectory, "subdirectory1");
        if (!subDirectory1.exists()) {
            subDirectory1.mkdirs();
        }
        File subDirectory2 = new File(mixedDirectory, "subdirectory2");
        if (!subDirectory2.exists()) {
            subDirectory2.mkdirs();
        }
        File file1 = new File(subDirectory1, "file1.txt");
        File file2 = new File(subDirectory2, "file2.txt");
        try {
            file1.createNewFile();
            file2.createNewFile();
        } catch (Exception e) {
            e.printStackTrace();
        }
        DirectoryExplorer.exploreDirectory(mixedDirectory);
    }
}


import java.util.Arrays;
class NeuralLayer {
    float[][] weights;
    float[][] biases;
    float[][] dWeights;
    float[][] dBiases;
    float[][] weightMomentums;
    float[][] biasMomentums;
    float[][] weightVelocities;
    float[][] biasVelocities;
    public NeuralLayer(int inputSize, int size) {
        weights = new float[size][inputSize];
        biases = new float[size][1];
        for (float[] row : weights) {
            Arrays.fill(row, 0.1f);
        }
        for (float[] row : biases) {
            Arrays.fill(row, 0.1f);
        }
    }
    public void updateWeightsAndBiases(float learningRate, float beta1, float beta2, float epsilon, int iteration) {
        if (weightMomentums == null) {
            weightMomentums = new float[weights.length][weights[0].length];
            biasMomentums = new float[biases.length][biases[0].length];
            weightVelocities = new float[weights.length][weights[0].length];
            biasVelocities = new float[biases.length][biases[0].length];
        }
        for (int i = 0; i < weights.length; i++) {
            for (int j = 0; j < weights[0].length; j++) {
                weightMomentums[i][j] = beta1 * weightMomentums[i][j] + (1 - beta1) * dWeights[i][j];
                float weightMomentumsCorrected = weightMomentums[i][j] / (1 - (float)Math.pow(beta1, iteration + 1));
                weightVelocities[i][j] = beta2 * weightVelocities[i][j] + (1 - beta2) * (dWeights[i][j] * dWeights[i][j]);
                float weightVelocitiesCorrected = weightVelocities[i][j] / (1 - (float)Math.pow(beta2, iteration + 1));
                weights[i][j] -= learningRate * weightMomentumsCorrected / (Math.sqrt(weightVelocitiesCorrected) + epsilon);
            }
        }
        for (int i = 0; i < biases.length; i++) {
            for (int j = 0; j < biases[0].length; j++) {
                biasMomentums[i][j] = beta1 * biasMomentums[i][j] + (1 - beta1) * dBiases[i][j];
                float biasMomentumsCorrected = biasMomentums[i][j] / (1 - (float)Math.pow(beta1, iteration + 1));
                biasVelocities[i][j] = beta2 * biasVelocities[i][j] + (1 - beta2) * (dBiases[i][j] * dBiases[i][j]);
                float biasVelocitiesCorrected = biasVelocities[i][j] / (1 - (float)Math.pow(beta2, iteration + 1));
                biases[i][j] -= learningRate * biasMomentumsCorrected / (Math.sqrt(biasVelocitiesCorrected) + epsilon);
            }
        }
    }
}
public class AdamOptimizerExample {
    public static void main(String[] args) {
        NeuralLayer layer = new NeuralLayer(3, 2);
        layer.dWeights = new float[][]{{0.1f, 0.2f, 0.3f}, {0.4f, 0.5f, 0.6f}};
        layer.dBiases = new float[][]{{0.1f}, {0.2f}};
        layer.updateWeightsAndBiases(0.01f, 0.9f, 0.999f, 1e-8f, 1);
        System.out.println("Updated Weights:");
        for (float[] row : layer.weights) {
            System.out.println(Arrays.toString(row));
        }
        System.out.println("Updated Biases:");
        for (float[] row : layer.biases) {
            System.out.println(Arrays.toString(row));
        }
    }
}

请实现一个Java方法，该方法用于更新神经网络中的参数，采用Adam优化算法。给定一个神经网络层对象，该对象包含权重、偏置及其梯度（dWeights和dBiases），以及用于Adam算法的动量（momentums）和速度（velocities）。你需要根据Adam算法更新这个层的权重和偏置。请注意，你需要首先检查是否已经初始化了动量和速度的存储空间，如果没有，则需要初始化为与权重和偏置同形状的零矩阵。此外，确保你的方法能够处理不同的学习率、beta1、beta2和epsilon值。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.Arrays;
class NeuralLayer {
    float[][] weights;
    float[][] biases;
    float[][] dWeights;
    float[][] dBiases;
    float[][] weightMomentums;
    float[][] biasMomentums;
    float[][] weightVelocities;
    float[][] biasVelocities;
    public NeuralLayer(int inputSize, int size) {
    }
    public void updateWeightsAndBiases(float learningRate, float beta1, float beta2, float epsilon, int iteration) {
    }
}
```

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
class NeuralLayerTest {
    @Test
    void testInitialization() {
        NeuralLayer layer = new NeuralLayer(3, 2);
        for (float[] row : layer.weights) {
            for (float value : row) {
                assertEquals(0.1f, value);
            }
        }
        for (float[] row : layer.biases) {
            for (float value : row) {
                assertEquals(0.1f, value);
            }
        }
    }
    @Test
    void testUpdateWeightsAndBiases() {
        NeuralLayer layer = new NeuralLayer(3, 2);
        layer.dWeights = new float[][]{{0.1f, 0.2f, 0.3f}, {0.4f, 0.5f, 0.6f}};
        layer.dBiases = new float[][]{{0.1f}, {0.2f}};
        layer.updateWeightsAndBiases(0.01f, 0.9f, 0.999f, 1e-8f, 1);
        assertNotNull(layer.weights);
        assertNotNull(layer.biases);
    }
    @Test
    void testUpdateWeightsAndBiasesMultipleIterations() {
        NeuralLayer layer = new NeuralLayer(3, 2);
        layer.dWeights = new float[][]{{0.1f, 0.2f, 0.3f}, {0.4f, 0.5f, 0.6f}};
        layer.dBiases = new float[][]{{0.1f}, {0.2f}};
        for (int i = 1; i <= 5; i++) {
            layer.updateWeightsAndBiases(0.01f, 0.9f, 0.999f, 1e-8f, i);
        }
        assertNotNull(layer.weights);
        assertNotNull(layer.biases);
    }
    @Test
    void testInitialMomentumAndVelocitiesAreNull() {
        NeuralLayer layer = new NeuralLayer(3, 2);
        assertNull(layer.weightMomentums);
        assertNull(layer.biasMomentums);
        assertNull(layer.weightVelocities);
        assertNull(layer.biasVelocities);
    }
    @Test
    void testMomentumAndVelocitiesAfterUpdate() {
        NeuralLayer layer = new NeuralLayer(3, 2);
        layer.dWeights = new float[][]{{0.1f, 0.2f, 0.3f}, {0.4f, 0.5f, 0.6f}};
        layer.dBiases = new float[][]{{0.1f}, {0.2f}};
        layer.updateWeightsAndBiases(0.01f, 0.9f, 0.999f, 1e-8f, 1);
        assertNotNull(layer.weightMomentums);
        assertNotNull(layer.biasMomentums);
        assertNotNull(layer.weightVelocities);
        assertNotNull(layer.biasVelocities);
    }
}


import java.util.Date;
import java.util.HashMap;
import java.util.Map;
public class StudentUpdateService {
    private static Map<Integer, StudentEntity> studentDatabase = new HashMap<>();
    static {
        studentDatabase.put(1, new StudentEntity(1, "张三", new Date()));
        studentDatabase.put(2, new StudentEntity(2, "李四", new Date()));
    }
    public static Callback updateStudent(StudentEntity studentEntity) {
        Date now = new Date();
        for (StudentEntity entity : studentDatabase.values()) {
            if (entity.getName().equals(studentEntity.getName()) && !entity.getId().equals(studentEntity.getId())) {
                return Callback.error("学生姓名已经存在!");
            }
        }
        studentEntity.setUpdateTime(now);
        studentDatabase.put(studentEntity.getId(), studentEntity);
        return Callback.success(true);
    }
    public static void main(String[] args) {
        Callback result1 = updateStudent(new StudentEntity(3, "王五", null));
        System.out.println(result1.getMessage());
        Callback result2 = updateStudent(new StudentEntity(2, "张三", null));
        System.out.println(result2.getMessage());
    }
}
class StudentEntity {
    private Integer id;
    private String name;
    private Date updateTime;
    public StudentEntity(Integer id, String name, Date updateTime) {
        this.id = id;
        this.name = name;
        this.updateTime = updateTime;
    }
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Date getUpdateTime() {
        return updateTime;
    }
    public void setUpdateTime(Date updateTime) {
        this.updateTime = updateTime;
    }
}
class Callback {
    private boolean success;
    private String message;
    private Callback(boolean success, String message) {
        this.success = success;
        this.message = message;
    }
    public static Callback success(boolean success) {
        return new Callback(success, "更新成功!");
    }
    public static Callback error(String message) {
        return new Callback(false, message);
    }
    public boolean isSuccess() {
        return success;
    }
    public String getMessage() {
        return message;
    }
}

请编写一个Java方法，用于更新学生信息。该方法接收一个学生实体作为参数，如果学生的姓名在数据库中已存在，则不更新信息并返回一个错误信息；如果学生的姓名不存在，则更新学生信息，并记录更新时间。更新成功后，返回成功的消息。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
public class StudentUpdateService {
    private static Map<Integer, StudentEntity> studentDatabase = new HashMap<>();
    static {
    }
    public static Callback updateStudent(StudentEntity studentEntity) {
    }
}
class StudentEntity {
    private Integer id;
    private String name;
    private Date updateTime;
    public StudentEntity(Integer id, String name, Date updateTime) {
    }
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
    }
    public Date getUpdateTime() {
        return updateTime;
    }
    public void setUpdateTime(Date updateTime) {
    }
}
class Callback {
    private boolean success;
    private String message;
    private Callback(boolean success, String message) {
    }
    public static Callback success(boolean success) {
    }
    public static Callback error(String message) {
    }
    public boolean isSuccess() {
        return success;
    }
    public String getMessage() {
        return message;
    }
}
```

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
import java.util.Date;
public class StudentUpdateServiceTest {
    @Test
    public void testUpdateStudent_Success_NewStudent() {
        StudentEntity newStudent = new StudentEntity(3, "王五", null);
        Callback result = StudentUpdateService.updateStudent(newStudent);
        assertTrue(result.isSuccess());
        assertEquals("更新成功!", result.getMessage());
    }
    @Test
    public void testUpdateStudent_Error_NameExists() {
        StudentEntity newStudent = new StudentEntity(2, "张三", null);
        Callback result = StudentUpdateService.updateStudent(newStudent);
        assertFalse(result.isSuccess());
        assertEquals("学生姓名已经存在!", result.getMessage());
    }
    @Test
    public void testUpdateStudent_Success_UpdateExistingStudent() {
        StudentEntity existingStudent = new StudentEntity(1, "张三", null);
        Callback result = StudentUpdateService.updateStudent(existingStudent);
        assertTrue(result.isSuccess());
        assertEquals("更新成功!", result.getMessage());
        assertNotNull(existingStudent.getUpdateTime());
    }
    @Test
    public void testUpdateStudent_Success_UpdateDifferentName() {
        StudentEntity newStudent = new StudentEntity(2, "刘备", null);
        Callback result = StudentUpdateService.updateStudent(newStudent);
        assertTrue(result.isSuccess());
        assertEquals("更新成功!", result.getMessage());
    }
    @Test
    public void testUpdateStudent_Success_AddAnotherStudent() {
        StudentEntity newStudent = new StudentEntity(4, "赵六", null);
        Callback result = StudentUpdateService.updateStudent(newStudent);
        assertTrue(result.isSuccess());
        assertEquals("更新成功!", result.getMessage());
    }
}


import java.util.HashMap;
import java.util.Map;
public class DatabaseConfigGenerator {
    public Map<String, String> generateHibernateConfig() {
        HashMap<String, String> config = new HashMap<>();
        config.put("hibernate.dialect", "org.hibernate.dialect.MySQL5Dialect");
        config.put("hibernate.physical_naming_strategy", "org.springframework.boot.orm.jpa.hibernate.SpringPhysicalNamingStrategy");
        return config;
    }
    public static void main(String[] args) {
        DatabaseConfigGenerator configGenerator = new DatabaseConfigGenerator();
        Map<String, String> config = configGenerator.generateHibernateConfig();
        boolean correct = "org.hibernate.dialect.MySQL5Dialect".equals(config.get("hibernate.dialect")) &&
                          "org.springframework.boot.orm.jpa.hibernate.SpringPhysicalNamingStrategy".equals(config.get("hibernate.physical_naming_strategy"));
        System.out.println("配置信息生成" + (correct ? "正确" : "错误"));
    }
}

请编写一个Java方法，该方法用于生成数据库配置信息。这些配置信息将被用于配置Hibernate框架以适应特定的数据库方言和命名策略。请确保返回一个包含数据库方言和命名策略的Map对象。我们需要关注以下两个配置项：

1. 数据库方言（hibernate.dialect），假设我们使用的是MySQL5方言。
2. 命名策略（hibernate.naming.physical_strategy），假设我们使用的是Spring框架提供的物理命名策略。

请确保你的代码完全独立，包括必要的包导入。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.HashMap;
import java.util.Map;
public class DatabaseConfigGenerator {
    public Map<String, String> generateHibernateConfig() {
    }
}
```

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
import java.util.Map;
import java.util.HashMap;
public class DatabaseConfigGeneratorTest {
    @Test
    public void testGenerateHibernateConfig_NotNull() {
        DatabaseConfigGenerator configGenerator = new DatabaseConfigGenerator();
        Map<String, String> config = configGenerator.generateHibernateConfig();
        assertNotNull(config, "Config map should not be null");
    }
    @Test
    public void testGenerateHibernateConfig_ContainsDialect() {
        DatabaseConfigGenerator configGenerator = new DatabaseConfigGenerator();
        Map<String, String> config = configGenerator.generateHibernateConfig();
        assertEquals("org.hibernate.dialect.MySQL5Dialect", config.get("hibernate.dialect"), "Config should contain correct hibernate.dialect");
    }
    @Test
    public void testGenerateHibernateConfig_ContainsNamingStrategy() {
        DatabaseConfigGenerator configGenerator = new DatabaseConfigGenerator();
        Map<String, String> config = configGenerator.generateHibernateConfig();
        assertEquals("org.springframework.boot.orm.jpa.hibernate.SpringPhysicalNamingStrategy", config.get("hibernate.physical_naming_strategy"), "Config should contain correct hibernate.physical_naming_strategy");
    }
    @Test
    public void testGenerateHibernateConfig_MapSize() {
        DatabaseConfigGenerator configGenerator = new DatabaseConfigGenerator();
        Map<String, String> config = configGenerator.generateHibernateConfig();
        assertEquals(2, config.size(), "Config map should contain exactly 2 entries");
    }
    @Test
    public void testGenerateHibernateConfig_NoExtraKeys() {
        DatabaseConfigGenerator configGenerator = new DatabaseConfigGenerator();
        Map<String, String> config = configGenerator.generateHibernateConfig();
        assertTrue(config.containsKey("hibernate.dialect") && config.containsKey("hibernate.physical_naming_strategy"), "Config should only contain specific keys");
    }
}


import java.util.ArrayList;
public class EvenNumbersFilter {
    public static int[] filterEvenNumbers(int[] numbers) {
        ArrayList<Integer> evenNumbersList = new ArrayList<>();
        for (int number : numbers) {
            if (number % 2 == 0) {
                evenNumbersList.add(number);
            }
        }
        int[] evenNumbers = new int[evenNumbersList.size()];
        for (int i = 0; i < evenNumbersList.size(); i++) {
            evenNumbers[i] = evenNumbersList.get(i);
        }
        return evenNumbers;
    }
    public static void main(String[] args) {
        int[] inputNumbers = {1, 2, 3, 4, 5, 6};
        int[] expectedOutput = {2, 4, 6};
        int[] actualOutput = filterEvenNumbers(inputNumbers);
        boolean isCorrect = expectedOutput.length == actualOutput.length;
        for (int i = 0; i < expectedOutput.length && isCorrect; i++) {
            if (expectedOutput[i] != actualOutput[i]) {
                isCorrect = false;
            }
        }
        if (isCorrect) {
            System.out.println("解决方案正确！");
        } else {
            System.out.println("解决方案不正确。");
        }
    }
}

请编写一个Java程序，实现一个方法，该方法接收一个整数数组作为输入，并返回一个表示该数组中所有偶数的新数组。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.ArrayList;
public class EvenNumbersFilter {
    public static int[] filterEvenNumbers(int[] numbers) {
    }
}
```

import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.api.Test;
import java.util.Arrays;
public class EvenNumbersFilterTest {
    @Test
    public void testFilterEvenNumbers_withMixedNumbers() {
        int[] inputNumbers = {1, 2, 3, 4, 5, 6};
        int[] expectedOutput = {2, 4, 6};
        assertArrayEquals(expectedOutput, EvenNumbersFilter.filterEvenNumbers(inputNumbers));
    }
    @Test
    public void testFilterEvenNumbers_withAllEvenNumbers() {
        int[] inputNumbers = {2, 4, 6, 8, 10};
        int[] expectedOutput = {2, 4, 6, 8, 10};
        assertArrayEquals(expectedOutput, EvenNumbersFilter.filterEvenNumbers(inputNumbers));
    }
    @Test
    public void testFilterEvenNumbers_withAllOddNumbers() {
        int[] inputNumbers = {1, 3, 5, 7, 9};
        int[] expectedOutput = {};
        assertArrayEquals(expectedOutput, EvenNumbersFilter.filterEvenNumbers(inputNumbers));
    }
    @Test
    public void testFilterEvenNumbers_withNoNumbers() {
        int[] inputNumbers = {};
        int[] expectedOutput = {};
        assertArrayEquals(expectedOutput, EvenNumbersFilter.filterEvenNumbers(inputNumbers));
    }
    @Test
    public void testFilterEvenNumbers_withNegativeNumbers() {
        int[] inputNumbers = {-3, -2, -1, 0, 1, 2};
        int[] expectedOutput = {-2, 0, 2};
        assertArrayEquals(expectedOutput, EvenNumbersFilter.filterEvenNumbers(inputNumbers));
    }
}


import java.util.HashMap;
import java.util.Map;
public class LibraryService {
    private Map<String, Boolean> bookCatalog = new HashMap<>();
    public LibraryService() {
        bookCatalog.put("B001", false);
        bookCatalog.put("B002", false);
        bookCatalog.put("B003", false);
    }
    public String borrowBookById(String bookId) {
        Boolean isBorrowed = bookCatalog.get(bookId);
        if (isBorrowed == null) {
            return "错误：书籍ID不存在。";
        } else if (isBorrowed) {
            return "书籍已被借出。";
        } else {
            bookCatalog.put(bookId, true);
            return "书籍成功借出。";
        }
    }
    public static void main(String[] args) {
        LibraryService libraryService = new LibraryService();
        System.out.println(libraryService.borrowBookById("B001"));
        System.out.println(libraryService.borrowBookById("B004"));
        System.out.println(libraryService.borrowBookById("B001"));
    }
}

请编写一个Java方法，用于处理图书馆中书籍的借阅。当一个用户想要借阅一本书时，该方法将根据书籍的ID来更新书籍的状态，表示该书已被借出。如果操作成功，返回一个字符串消息表示书籍已成功借出，否则返回一个错误消息。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.HashMap;
import java.util.Map;
public class LibraryService {
    private Map<String, Boolean> bookCatalog = new HashMap<>();
    public LibraryService() {
    }
    public String borrowBookById(String bookId) {
    }
}
```

import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
public class LibraryServiceTest {
    private LibraryService libraryService;
    @BeforeEach
    void setUp() {
        libraryService = new LibraryService();
    }
    @Test
    void testBorrowBookById_Success() {
        String result = libraryService.borrowBookById("B001");
        assertEquals("书籍成功借出。", result);
    }
    @Test
    void testBorrowBookById_BookDoesNotExist() {
        String result = libraryService.borrowBookById("B004");
        assertEquals("错误：书籍ID不存在。", result);
    }
    @Test
    void testBorrowBookById_AlreadyBorrowed() {
        libraryService.borrowBookById("B002");
        String result = libraryService.borrowBookById("B002");
        assertEquals("书籍已被借出。", result);
    }
    @Test
    void testBorrowBookById_Null() {
        String result = libraryService.borrowBookById("B003");
        assertEquals("书籍成功借出。", result);
    }
    @Test
    void testBorrowBookById_SuccessWithDifferentBookId() {
        String result = libraryService.borrowBookById("B003");
        assertEquals("书籍成功借出。", result);
    }
}


import java.util.Arrays;
import java.util.List;
public class SimpleCalculator {
    public double add(double a, double b) {
        return a + b;
    }
    public double subtract(double a, double b) {
        return a - b;
    }
    public double multiply(double a, double b) {
        return a * b;
    }
    public double divide(double a, double b) {
        if (b == 0) {
            return Double.NaN;
        }
        return a / b;
    }
    public static void main(String[] args) {
        SimpleCalculator calculator = new SimpleCalculator();
        List<Double> results = Arrays.asList(
                calculator.add(5, 3),
                calculator.subtract(10, 4),
                calculator.multiply(2, 3),
                calculator.divide(8, 2),
                calculator.divide(5, 0)
        );
        System.out.println("计算结果：" + results);
    }
}

请编写一个Java程序，实现一个简单的计算器类`SimpleCalculator`。这个类应该能够执行基本的算术运算：加法、减法、乘法和除法。每个运算都应该通过一个方法实现，接收两个`double`类型的参数，并返回一个`double`类型的结果。请确保除法方法能够处理除数为零的情况，此时应返回`Double.NaN`。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.Arrays;
import java.util.List;
public class SimpleCalculator {
    public double add(double a, double b) {
    }
    public double subtract(double a, double b) {
    }
    public double multiply(double a, double b) {
    }
    public double divide(double a, double b) {
    }
}
```

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
public class SimpleCalculatorTest {
    @Test
    public void testAdd() {
        SimpleCalculator calculator = new SimpleCalculator();
        assertEquals(8.0, calculator.add(5, 3));
        assertEquals(14.0, calculator.add(10, 4));
    }
    @Test
    public void testSubtract() {
        SimpleCalculator calculator = new SimpleCalculator();
        assertEquals(6.0, calculator.subtract(10, 4));
        assertEquals(1.0, calculator.subtract(5, 4));
    }
    @Test
    public void testMultiply() {
        SimpleCalculator calculator = new SimpleCalculator();
        assertEquals(6.0, calculator.multiply(2, 3));
        assertEquals(0.0, calculator.multiply(0, 5));
    }
    @Test
    public void testDivide() {
        SimpleCalculator calculator = new SimpleCalculator();
        assertEquals(4.0, calculator.divide(8, 2));
        assertTrue(Double.isNaN(calculator.divide(5, 0)));
    }
    @Test
    public void testDivideByZero() {
        SimpleCalculator calculator = new SimpleCalculator();
        assertTrue(Double.isNaN(calculator.divide(5, 0)));
        assertTrue(Double.isNaN(calculator.divide(-5, 0)));
    }
}


import java.lang.Math;
public class Rectangle {
    private double length;
    private double width;
    public Rectangle(double length, double width) {
        this.length = length;
        this.width = width;
    }
    public double calculateArea() {
        return length * width;
    }
    public static void main(String[] args) {
        Rectangle rect1 = new Rectangle(5.0, 4.0);
        Rectangle rect2 = new Rectangle(7.5, 3.5);
        System.out.println("矩形1的面积: " + rect1.calculateArea());
        System.out.println("矩形2的面积: " + rect2.calculateArea());
    }
}

编写一个Java程序，用于计算一个矩形的面积。请确保你的程序满足以下要求：

- 你的程序应该包含一个名为`Rectangle`的类。
- 在`Rectangle`类中，应该有两个属性：`length`和`width`，分别用于存储矩形的长度和宽度。
- 类应该有一个构造函数，接受两个参数（长度和宽度），并据此初始化对象。
- 类中应该包含一个名为`calculateArea`的方法，该方法用于计算并返回矩形的面积。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.lang.Math;
public class Rectangle {
    private double length;
    private double width;
    public Rectangle(double length, double width) {
    }
    public double calculateArea() {
    }
}
```

import org.junit.Test;
import static org.junit.Assert.*;
public class RectangleTest {
    @Test
    public void testCalculateAreaPositiveNumbers() {
        Rectangle rect = new Rectangle(5.0, 4.0);
        assertEquals(20.0, rect.calculateArea(), 0.0001);
    }
    @Test
    public void testCalculateAreaZeroLength() {
        Rectangle rect = new Rectangle(0, 4.0);
        assertEquals(0.0, rect.calculateArea(), 0.0001);
    }
    @Test
    public void testCalculateAreaZeroWidth() {
        Rectangle rect = new Rectangle(5.0, 0);
        assertEquals(0.0, rect.calculateArea(), 0.0001);
    }
    @Test
    public void testCalculateAreaNegativeNumbers() {
        Rectangle rect = new Rectangle(-5.0, 4.0);
        assertEquals(-20.0, rect.calculateArea(), 0.0001);
    }
    @Test
    public void testCalculateAreaDecimalNumbers() {
        Rectangle rect = new Rectangle(7.5, 3.5);
        assertEquals(26.25, rect.calculateArea(), 0.0001);
    }
}


import java.util.HashMap;
public class StudentScoreManager {
    private HashMap<String, Integer> studentScores;
    public StudentScoreManager() {
        studentScores = new HashMap<>();
    }
    public void addStudentScore(String name, int score) {
        studentScores.put(name, score);
    }
    public int getStudentScore(String name) {
        return studentScores.getOrDefault(name, -1);
    }
    public static void main(String[] args) {
        StudentScoreManager manager = new StudentScoreManager();
        manager.addStudentScore("张三", 90);
        manager.addStudentScore("李四", 85);
        System.out.println("张三的分数是：" + manager.getStudentScore("张三"));
        System.out.println("李四的分数是：" + manager.getStudentScore("李四"));
        System.out.println("王五的分数是：" + manager.getStudentScore("王五"));
    }
}

请设计一个Java程序，实现一个简单的学生信息管理系统。该系统应该能够让用户存储学生的姓名和他们的分数，并且能够根据学生的姓名查询他们的分数。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.HashMap;
public class StudentScoreManager {
    private HashMap<String, Integer> studentScores;
    public StudentScoreManager() {}
    public void addStudentScore(String name, int score) {}
    public int getStudentScore(String name) { return 0; }
}
```

import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
public class StudentScoreManagerTest {
    private StudentScoreManager manager;
    @BeforeEach
    public void setUp() {
        manager = new StudentScoreManager();
    }
    @Test
    public void testAddStudentScoreAndRetrieve() {
        manager.addStudentScore("张三", 90);
        assertEquals(90, manager.getStudentScore("张三"));
    }
    @Test
    public void testGetStudentScoreForNonexistentStudent() {
        assertEquals(-1, manager.getStudentScore("王五"));
    }
    @Test
    public void testUpdateStudentScore() {
        manager.addStudentScore("李四", 85);
        manager.addStudentScore("李四", 95);
        assertEquals(95, manager.getStudentScore("李四"));
    }
    @Test
    public void testAddMultipleStudentScores() {
        manager.addStudentScore("张三", 90);
        manager.addStudentScore("李四", 85);
        assertEquals(90, manager.getStudentScore("张三"));
        assertEquals(85, manager.getStudentScore("李四"));
    }
    @Test
    public void testNegativeScore() {
        manager.addStudentScore("赵六", -10);
        assertEquals(-10, manager.getStudentScore("赵六"));
    }
}


import java.util.HashMap;
public class SafeAddToMap {
    public static void safeAdd(HashMap<String, String> map, String key, String value) {
        try {
            map.put(key, value);
        } catch (Exception e) {
        }
    }
    public static void main(String[] args) {
        HashMap<String, String> myMap = new HashMap<>();
        safeAdd(myMap, "key1", "value1");
        safeAdd(myMap, "key2", "value2");
        System.out.println(myMap);
    }
}

请编写一个Java方法，该方法能够安全地向一个`HashMap`中添加键值对。如果在添加过程中遇到任何异常，方法应该捕获这些异常并且忽略它们，确保程序的继续运行。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.HashMap;
public class SafeAddToMap {
    public static void safeAdd(HashMap<String, String> map, String key, String value) {
    }
}
```

import java.util.HashMap;
import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.api.Test;
public class SafeAddToMapTest {
    @Test
    public void testSafeAdd_NormalCase() {
        HashMap<String, String> map = new HashMap<>();
        SafeAddToMap.safeAdd(map, "testKey", "testValue");
        assertEquals("testValue", map.get("testKey"));
    }
    @Test
    public void testSafeAdd_NullKey() {
        HashMap<String, String> map = new HashMap<>();
        SafeAddToMap.safeAdd(map, null, "testValue");
        assertEquals("testValue", map.get(null));
    }
    @Test
    public void testSafeAdd_NullValue() {
        HashMap<String, String> map = new HashMap<>();
        SafeAddToMap.safeAdd(map, "testKey", null);
        assertNull(map.get("testKey"));
    }
    @Test
    public void testSafeAdd_NullMap() {
        HashMap<String, String> map = null;
        assertDoesNotThrow(() -> SafeAddToMap.safeAdd(map, "testKey", "testValue"));
    }
    @Test
    public void testSafeAdd_DuplicateKey() {
        HashMap<String, String> map = new HashMap<>();
        SafeAddToMap.safeAdd(map, "testKey", "initialValue");
        SafeAddToMap.safeAdd(map, "testKey", "newValue");
        assertEquals("newValue", map.get("testKey"));
    }
}


import java.util.ArrayList;
import java.util.List;
class UserInfoUpdater {
    static class UserInfo {
        String productName;
        int productQuantity;
        String shippedId;
        List<Integer> shippedInfo;
        int airNumber;
        List<Integer> airInformation;
        public UserInfo(String productName, int productQuantity, String shippedId, List<Integer> shippedInfo, int airNumber, List<Integer> airInformation) {
            this.productName = productName;
            this.productQuantity = productQuantity;
            this.shippedId = shippedId;
            this.shippedInfo = shippedInfo;
            this.airNumber = airNumber;
            this.airInformation = airInformation;
        }
    }
    public static List<UserInfo> updateUserInfo(List<UserInfo> users) {
        for (UserInfo user : users) {
            user.productName = user.productName.toUpperCase();
            user.productQuantity += 10;
            user.shippedId += "A";
            user.shippedInfo.set(user.shippedInfo.size() - 1, user.shippedInfo.get(user.shippedInfo.size() - 1) + 10);
            user.airNumber += 100;
            user.airInformation.set(user.airInformation.size() - 1, user.airInformation.get(user.airInformation.size() - 1) + 10);
        }
        return users;
    }
    public static void main(String[] args) {
        List<UserInfo> users = new ArrayList<>();
        users.add(new UserInfo("laptop", 20, "ID123", List.of(1, 2, 3), 500, List.of(100, 200, 300)));
        users.add(new UserInfo("tablet", 15, "ID456", List.of(4, 5, 6), 600, List.of(400, 500, 600)));
        users = updateUserInfo(users);
        for (UserInfo user : users) {
            System.out.println("ProductName: " + user.productName + ", ProductQuantity: " + user.productQuantity + ", ShippedId: " + user.shippedId + ", LastShippedInfo: " + user.shippedInfo.get(user.shippedInfo.size() - 1) + ", AirNumber: " + user.airNumber + ", LastAirInformation: " + user.airInformation.get(user.airInformation.size() - 1));
        }
    }
}

请设计一个流程，用于处理用户信息的一系列更新操作。给定一组用户信息，你需要按照以下步骤更新这些信息：

1. 将所有用户的产品名称转换为大写。
2. 所有用户的产品数量增加10。
3. 所有用户的发货ID增加"A"。
4. 所有用户的最后一个发货信息数组值增加10。
5. 所有用户的航空编号增加100。
6. 所有用户的最后一个航空信息数组值增加10。
7. 提取所有用户的最后一个航空信息数组值。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.ArrayList;
import java.util.List;
class UserInfoUpdater {
    static class UserInfo {
        String productName;
        int productQuantity;
        String shippedId;
        List<Integer> shippedInfo;
        int airNumber;
        List<Integer> airInformation;
        public UserInfo(String productName, int productQuantity, String shippedId, List<Integer> shippedInfo, int airNumber, List<Integer> airInformation) {
        }
    }
    public static List<UserInfo> updateUserInfo(List<UserInfo> users) {
        return users;
    }
}
```

import org.junit.jupiter.api.Test;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import static org.junit.jupiter.api.Assertions.*;
class UserInfoUpdaterTest {
    @Test
    void testUpdateUserInfoIncrementsProductQuantity() {
        List<UserInfoUpdater.UserInfo> users = new ArrayList<>();
        users.add(new UserInfoUpdater.UserInfo("laptop", 20, "ID123", Arrays.asList(1, 2, 3), 500, Arrays.asList(100, 200, 300)));
        List<UserInfoUpdater.UserInfo> updatedUsers = UserInfoUpdater.updateUserInfo(users);
        assertEquals(30, updatedUsers.get(0).productQuantity);
    }
    @Test
    void testUpdateUserInfoConvertsProductNameToUpperCase() {
        List<UserInfoUpdater.UserInfo> users = new ArrayList<>();
        users.add(new UserInfoUpdater.UserInfo("laptop", 20, "ID123", Arrays.asList(1, 2, 3), 500, Arrays.asList(100, 200, 300)));
        List<UserInfoUpdater.UserInfo> updatedUsers = UserInfoUpdater.updateUserInfo(users);
        assertEquals("LAPTOP", updatedUsers.get(0).productName);
    }
    @Test
    void testUpdateUserInfoAppendsToShippedId() {
        List<UserInfoUpdater.UserInfo> users = new ArrayList<>();
        users.add(new UserInfoUpdater.UserInfo("laptop", 20, "ID123", Arrays.asList(1, 2, 3), 500, Arrays.asList(100, 200, 300)));
        List<UserInfoUpdater.UserInfo> updatedUsers = UserInfoUpdater.updateUserInfo(users);
        assertEquals("ID123A", updatedUsers.get(0).shippedId);
    }
    @Test
    void testUpdateUserInfoIncrementsLastElementOfShippedInfo() {
        List<UserInfoUpdater.UserInfo> users = new ArrayList<>();
        users.add(new UserInfoUpdater.UserInfo("laptop", 20, "ID123", Arrays.asList(1, 2, 3), 500, Arrays.asList(100, 200, 300)));
        List<UserInfoUpdater.UserInfo> updatedUsers = UserInfoUpdater.updateUserInfo(users);
        assertEquals(13, updatedUsers.get(0).shippedInfo.get(2));
    }
    @Test
    void testUpdateUserInfoIncrementsAirNumber() {
        List<UserInfoUpdater.UserInfo> users = new ArrayList<>();
        users.add(new UserInfoUpdater.UserInfo("laptop", 20, "ID123", Arrays.asList(1, 2, 3), 500, Arrays.asList(100, 200, 300)));
        List<UserInfoUpdater.UserInfo> updatedUsers = UserInfoUpdater.updateUserInfo(users);
        assertEquals(600, updatedUsers.get(0).airNumber);
    }
    @Test
    void testUpdateUserInfoIncrementsLastElementOfAirInformation() {
        List<UserInfoUpdater.UserInfo> users = new ArrayList<>();
        users.add(new UserInfoUpdater.UserInfo("laptop", 20, "ID123", Arrays.asList(1, 2, 3), 500, Arrays.asList(100, 200, 300)));
        List<UserInfoUpdater.UserInfo> updatedUsers = UserInfoUpdater.updateUserInfo(users);
        assertEquals(310, updatedUsers.get(0).airInformation.get(2));
    }
}


import java.util.List;
import java.util.ArrayList;
class User {
    private String name;
    private List<Book> collection;
    public User(String name) {
        this.name = name;
        this.collection = new ArrayList<>();
    }
    public void addBookToCollection(Book book) {
        if (!collection.contains(book)) {
            collection.add(book);
        }
    }
    public List<Book> getCollection() {
        return collection;
    }
    public void setCollection(List<Book> collection) {
        this.collection = collection;
    }
}
class Book {
    private String title;
    public Book(String title) {
        this.title = title;
    }
    public String getTitle() {
        return title;
    }
}
class CollectionManager {
    public void deleteBookFromCollection(User user, Book book) {
        List<Book> collection = user.getCollection();
        if (collection.contains(book)) {
            collection.remove(book);
            user.setCollection(collection);
        }
    }
}
public class Main {
    public static void main(String[] args) {
        User user = new User("张三");
        Book book1 = new Book("Java编程思想");
        Book book2 = new Book("Effective Java");
        user.addBookToCollection(book1);
        user.addBookToCollection(book2);
        CollectionManager manager = new CollectionManager();
        manager.deleteBookFromCollection(user, book1);
        if (!user.getCollection().contains(book1) && user.getCollection().contains(book2)) {
            System.out.println("测试通过");
        } else {
            System.out.println("测试失败");
        }
    }
}

假设你正在开发一个图书管理系统，其中包含一个功能是允许用户将图书从他们的收藏列表中删除。请编写一个Java方法来实现这个功能。该方法接收两个参数：一个是用户对象，另一个是要从收藏中删除的图书对象。你需要从用户的收藏列表中找到这本书，并将其删除。如果这本书在用户的收藏列表中不存在，则不执行任何操作。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.List;
import java.util.ArrayList;
class User {
    private String name;
    private List<Book> collection;
    public User(String name) {
    }
    public void addBookToCollection(Book book) {
    }
    public List<Book> getCollection() {
    }
    public void setCollection(List<Book> collection) {
    }
}
class Book {
    private String title;
    public Book(String title) {
    }
    public String getTitle() {
    }
}
class CollectionManager {
    public void deleteBookFromCollection(User user, Book book) {
    }
}
```

import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import java.util.List;
import java.util.ArrayList;
class UserTest {
    private User user;
    private Book book1;
    private Book book2;
    @BeforeEach
    void setUp() {
        user = new User("张三");
        book1 = new Book("Java编程思想");
        book2 = new Book("Effective Java");
    }
    @Test
    void testAddBookToCollection() {
        user.addBookToCollection(book1);
        assertTrue(user.getCollection().contains(book1));
    }
    @Test
    void testGetCollection() {
        user.addBookToCollection(book1);
        user.addBookToCollection(book2);
        List<Book> collection = user.getCollection();
        assertEquals(2, collection.size());
        assertTrue(collection.contains(book1));
        assertTrue(collection.contains(book2));
    }
    @Test
    void testSetCollection() {
        List<Book> newCollection = new ArrayList<>();
        newCollection.add(book1);
        user.setCollection(newCollection);
        assertEquals(newCollection, user.getCollection());
    }
}
class CollectionManagerTest {
    private User user;
    private Book book1;
    private Book book2;
    private CollectionManager manager;
    @BeforeEach
    void setUp() {
        user = new User("张三");
        book1 = new Book("Java编程思想");
        book2 = new Book("Effective Java");
        manager = new CollectionManager();
        user.addBookToCollection(book1);
        user.addBookToCollection(book2);
    }
    @Test
    void testDeleteBookFromCollection() {
        manager.deleteBookFromCollection(user, book1);
        assertFalse(user.getCollection().contains(book1));
    }
    @Test
    void testDeleteBookFromCollectionNotInList() {
        Book book3 = new Book("Java核心技术卷I");
        manager.deleteBookFromCollection(user, book3);
        assertTrue(user.getCollection().contains(book1));
        assertTrue(user.getCollection().contains(book2));
    }
    @Test
    void testDeleteBookFromEmptyCollection() {
        User newUser = new User("李四");
        manager.deleteBookFromCollection(newUser, book1);
        assertTrue(newUser.getCollection().isEmpty());
    }
}


import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
public class CustomThreadPoolCreator {
    public ThreadPoolExecutor createCustomThreadPool(int corePoolSize, int maxPoolSize, int queueCapacity, String namePrefix) {
        ThreadPoolExecutor executor = new ThreadPoolExecutor(
            corePoolSize,
            maxPoolSize,
            60L, TimeUnit.SECONDS,
            new LinkedBlockingQueue<>(queueCapacity),
            new CustomThreadFactory(namePrefix),
            new ThreadPoolExecutor.CallerRunsPolicy());
        return executor;
    }
    static class CustomThreadFactory implements java.util.concurrent.ThreadFactory {
        private final String namePrefix;
        private int threadId = 1;
        public CustomThreadFactory(String namePrefix) {
            this.namePrefix = namePrefix;
        }
        @Override
        public Thread newThread(Runnable r) {
            Thread t = new Thread(r, namePrefix + "-thread-" + threadId++);
            return t;
        }
    }
    public static void main(String[] args) {
        CustomThreadPoolCreator creator = new CustomThreadPoolCreator();
        ThreadPoolExecutor executor = creator.createCustomThreadPool(2, 4, 10, "TestPool");
        executor.execute(() -> System.out.println(Thread.currentThread().getName() + " is running"));
        executor.shutdown();
    }
}

请设计一个Java方法，用于创建一个自定义的线程池。这个线程池需要能够根据传入的参数动态地设置其核心线程数、最大线程数、队列容量以及线程名称前缀。此外，当线程池达到最大容量时，应有一个策略来处理新的任务。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
public class CustomThreadPoolCreator {
    public ThreadPoolExecutor createCustomThreadPool(int corePoolSize, int maxPoolSize, int queueCapacity, String namePrefix) {
    }
    static class CustomThreadFactory implements java.util.concurrent.ThreadFactory {
        private final String namePrefix;
        private int threadId = 1;
        public CustomThreadFactory(String namePrefix) {
        }
        @Override
        public Thread newThread(Runnable r) {
        }
    }
}
```

import org.junit.Before;
import org.junit.Test;
import java.util.concurrent.ThreadPoolExecutor;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
public class CustomThreadPoolCreatorTest {
    private CustomThreadPoolCreator creator;
    @Before
    public void setUp() {
        creator = new CustomThreadPoolCreator();
    }
    @Test
    public void testCreateCustomThreadPool_CorePoolSize() {
        ThreadPoolExecutor executor = creator.createCustomThreadPool(2, 4, 10, "TestPool");
        assertEquals(2, executor.getCorePoolSize());
    }
    @Test
    public void testCreateCustomThreadPool_MaxPoolSize() {
        ThreadPoolExecutor executor = creator.createCustomThreadPool(2, 4, 10, "TestPool");
        assertEquals(4, executor.getMaximumPoolSize());
    }
    @Test
    public void testCreateCustomThreadPool_QueueCapacity() {
        ThreadPoolExecutor executor = creator.createCustomThreadPool(2, 4, 10, "TestPool");
        assertEquals(10, executor.getQueue().remainingCapacity());
    }
    @Test
    public void testCreateCustomThreadPool_NamePrefix() {
        ThreadPoolExecutor executor = creator.createCustomThreadPool(2, 4, 10, "TestPool");
        executor.execute(() -> {
            String threadName = Thread.currentThread().getName();
            assertEquals(true, threadName.startsWith("TestPool-thread-"));
        });
    }
    @Test
    public void testCreateCustomThreadPool_NotNullExecutor() {
        ThreadPoolExecutor executor = creator.createCustomThreadPool(2, 4, 10, "TestPool");
        assertNotNull(executor);
    }
}


import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
public class LibrarySystem {
    public static CompletableFuture<String> asyncUpdateBookInfo(String bookId, String newTitle, String newAuthor) {
        return CompletableFuture.supplyAsync(() -> {
            boolean updateResult = updateBookInfo(bookId, newTitle, newAuthor);
            if (updateResult) {
                return "Update successful";
            } else {
                return "Update failed";
            }
        });
    }
    private static boolean updateBookInfo(String bookId, String newTitle, String newAuthor) {
        return true;
    }
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        CompletableFuture<String> updateFuture = asyncUpdateBookInfo("123", "新标题", "新作者");
        String result = updateFuture.get();
        System.out.println(result);
    }
}

假设你正在开发一个用于管理图书馆书籍的系统，你需要实现一个功能来更新图书信息。请编写一个Java方法，该方法能够异步更新图书的信息，并且在更新完成后返回一个表示操作结果的字符串。

你需要实现的方法名为`asyncUpdateBookInfo`，它接受三个参数：`bookId`（图书的ID，类型为`String`），`newTitle`（图书的新标题，类型为`String`），和`newAuthor`（图书的新作者，类型为`String`）。该方法应该异步地更新图书信息，并在更新成功时返回`"Update successful"`，如果遇到任何错误则返回`"Update failed"`。

请使用`CompletableFuture`来实现异步操作，并假设你已经有一个同步方法`updateBookInfo(String bookId, String newTitle, String newAuthor)`可以调用，该方法在更新成功时返回`true`，失败时返回`false`。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
public class LibrarySystem {
    public static CompletableFuture<String> asyncUpdateBookInfo(String bookId, String newTitle, String newAuthor) {
        return CompletableFuture.supplyAsync(() -> {
        });
    }
    private static boolean updateBookInfo(String bookId, String newTitle, String newAuthor) {
        return true;
    }
}
```

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;
public class LibrarySystemTest {
    @Test
    public void testAsyncUpdateBookInfoSuccessful() throws ExecutionException, InterruptedException {
        CompletableFuture<String> updateFuture = LibrarySystem.asyncUpdateBookInfo("123", "新标题", "新作者");
        String result = updateFuture.get();
        assertEquals("Update successful", result);
    }
    @Test
    public void testAsyncUpdateBookInfoDifferentBookId() throws ExecutionException, InterruptedException {
        CompletableFuture<String> updateFuture = LibrarySystem.asyncUpdateBookInfo("456", "Another Title", "Another Author");
        String result = updateFuture.get();
        assertEquals("Update successful", result);
    }
    @Test
    public void testAsyncUpdateBookInfoEmptyTitle() throws ExecutionException, InterruptedException {
        CompletableFuture<String> updateFuture = LibrarySystem.asyncUpdateBookInfo("123", "", "新作者");
        String result = updateFuture.get();
        assertEquals("Update successful", result);
    }
    @Test
    public void testAsyncUpdateBookInfoEmptyAuthor() throws ExecutionException, InterruptedException {
        CompletableFuture<String> updateFuture = LibrarySystem.asyncUpdateBookInfo("123", "新标题", "");
        String result = updateFuture.get();
        assertEquals("Update successful", result);
    }
    @Test
    public void testAsyncUpdateBookInfoEmptyFields() throws ExecutionException, InterruptedException {
        CompletableFuture<String> updateFuture = LibrarySystem.asyncUpdateBookInfo("123", "", "");
        String result = updateFuture.get();
        assertEquals("Update successful", result);
    }
}


import java.util.regex.Pattern;
public class EmailValidator {
    public static boolean isValidEmail(String email) {
        String emailRegex = "^[\\w-\\.]+@[\\w-]+\\.[\\w-]{2,}$";
        Pattern pattern = Pattern.compile(emailRegex);
        if (email == null) {
            return false;
        }
        return pattern.matcher(email).matches();
    }
    public static void main(String[] args) {
        System.out.println(isValidEmail("example@example.com"));
        System.out.println(isValidEmail("example@example"));
        System.out.println(isValidEmail("example@.com"));
        System.out.println(isValidEmail("example.com"));
        System.out.println(isValidEmail("@example.com"));
        System.out.println(isValidEmail(" example@example.com "));
        System.out.println(isValidEmail("example@example.com."));
        System.out.println(isValidEmail("exa mple@example.com"));
    }
}

请编写一个Java方法，用于验证一个字符串是否符合电子邮件地址的格式要求。该方法应该接受一个字符串参数，如果该字符串是一个有效的电子邮件地址，则返回`true`，否则返回`false`。有效的电子邮件地址定义为：它必须包含`@`符号，且`@`符号前后都应有字符，同时，`@`符号后面必须有至少一个`.`符号，且`.`符号后也应有字符。请注意，电子邮件地址中不应包含空格。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.regex.Pattern;
public class EmailValidator {
    public static boolean isValidEmail(String email) {
    }
}
```

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
public class EmailValidatorTest {
    @Test
    public void testValidEmail() {
        Assertions.assertTrue(EmailValidator.isValidEmail("example@example.com"));
    }
    @Test
    public void testInvalidEmailWithoutDomain() {
        Assertions.assertFalse(EmailValidator.isValidEmail("example@example"));
    }
    @Test
    public void testInvalidEmailWithoutUsername() {
        Assertions.assertFalse(EmailValidator.isValidEmail("example@.com"));
    }
    @Test
    public void testInvalidEmailMissingAtSymbol() {
        Assertions.assertFalse(EmailValidator.isValidEmail("example.com"));
    }
    @Test
    public void testInvalidEmailWhitespace() {
        Assertions.assertFalse(EmailValidator.isValidEmail(" example@example.com "));
    }
    @Test
    public void testInvalidEmailSpecialCharacter() {
        Assertions.assertFalse(EmailValidator.isValidEmail("example@example.com."));
    }
    @Test
    public void testInvalidEmailSpaceInAddress() {
        Assertions.assertFalse(EmailValidator.isValidEmail("exa mple@example.com"));
    }
}


import java.text.ParseException;
import java.text.SimpleDateFormat;
public class DateTimeFormatter {
    public static String validateDateTime(String input) {
        SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        formatter.setLenient(false);
        try {
            formatter.parse(input);
            return "输入有效";
        } catch (ParseException e) {
            return "输入格式错误，请重新输入";
        }
    }
    public static void main(String[] args) {
        String[] testInputs = {
            "2023-04-01 12:00:00",
            "2023-02-29 12:00:00",
            "2023-04-01 25:00:00",
            "2023/04/01 12:00:00"
        };
        for (String input : testInputs) {
            System.out.println(validateDateTime(input));
        }
    }
}

请编写一个Java程序，用于格式化用户输入的日期和时间。用户将以字符串形式输入日期和时间，格式应为"yyyy-MM-dd HH:mm:ss"。你需要确保输入的日期和时间是有效的，如果输入格式不正确，程序应返回一个特定的错误信息。请使用`SimpleDateFormat`和`ParseException`来完成这个任务，并且在验证过程中，如果日期和时间有效，返回"输入有效"，如果不有效，返回"输入格式错误，请重新输入"。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.text.ParseException;
import java.text.SimpleDateFormat;
public class DateTimeFormatter {
    public static String validateDateTime(String input) {
    }
}
```

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
public class DateTimeFormatterTest {
    @Test
    public void testValidDateTime() {
        String input = "2023-04-01 12:00:00";
        String result = DateTimeFormatter.validateDateTime(input);
        assertEquals("输入有效", result);
    }
    @Test
    public void testInvalidDateFormat() {
        String input = "2023/04/01 12:00:00";
        String result = DateTimeFormatter.validateDateTime(input);
        assertEquals("输入格式错误，请重新输入", result);
    }
    @Test
    public void testInvalidDateTimeHour() {
        String input = "2023-04-01 25:00:00";
        String result = DateTimeFormatter.validateDateTime(input);
        assertEquals("输入格式错误，请重新输入", result);
    }
    @Test
    public void testInvalidDateLeapYear() {
        String input = "2023-02-29 12:00:00";
        String result = DateTimeFormatter.validateDateTime(input);
        assertEquals("输入格式错误，请重新输入", result);
    }
    @Test
    public void testEdgeCaseValidDateTime() {
        String input = "2023-12-31 23:59:59";
        String result = DateTimeFormatter.validateDateTime(input);
        assertEquals("输入有效", result);
    }
}


import java.util.Arrays;
import java.util.List;
public class LandClassification {
    public static boolean isBuildingArea(int type) {
        List<Integer> buildingTypes = Arrays.asList(1, 2, 3, 4);
        return buildingTypes.contains(type);
    }
    public static void checkFunction() {
        assert isBuildingArea(1) : "住宅区应该被识别为建筑区域";
        assert isBuildingArea(2) : "商业区应该被识别为建筑区域";
        assert isBuildingArea(3) : "工业区应该被识别为建筑区域";
        assert isBuildingArea(4) : "公共设施区应该被识别为建筑区域";
        assert !isBuildingArea(5) : "绿地区域不应该被识别为建筑区域";
        assert !isBuildingArea(6) : "道路不应该被识别为建筑区域";
        assert !isBuildingArea(0) : "未分类区域不应该被识别为建筑区域";
        System.out.println("所有测试通过！");
    }
    public static void main(String[] args) {
        checkFunction();
    }
}

请编写一个Java方法，用于判断一个地块是否属于建筑区域。地块的类型通过一个整数`type`来表示，其中：

- `1` 表示住宅区
- `2` 表示商业区
- `3` 表示工业区
- `4` 表示公共设施区
- `5` 表示绿地区域
- `6` 表示道路
- 其他数字表示未分类区域

如果地块属于住宅区、商业区、工业区或公共设施区，则认为该地块是建筑区域。请实现这个方法。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.Arrays;
import java.util.List;
public class LandClassification {
    public static boolean isBuildingArea(int type) {
    }
    public static void checkFunction() {
    }
}
```

import org.junit.Test;
import static org.junit.Assert.*;
public class LandClassificationTest {
    @Test
    public void testIsBuildingArea_ForResidentialArea() {
        assertTrue(LandClassification.isBuildingArea(1));
    }
    @Test
    public void testIsBuildingArea_ForCommercialArea() {
        assertTrue(LandClassification.isBuildingArea(2));
    }
    @Test
    public void testIsBuildingArea_ForIndustrialArea() {
        assertTrue(LandClassification.isBuildingArea(3));
    }
    @Test
    public void testIsBuildingArea_ForUnknownArea() {
        assertFalse(LandClassification.isBuildingArea(5));
    }
    @Test
    public void testIsBuildingArea_ForRoads() {
        assertFalse(LandClassification.isBuildingArea(6));
    }
}


import java.util.Optional;
public class TokenValidator {
    public Boolean validateAccessToken(String accessToken) {
        if (!isTokenFormatValid(accessToken)) {
            return false;
        }
        String storedToken = "abc123";
        return accessToken.equals(storedToken);
    }
    private boolean isTokenFormatValid(String token) {
        return token != null && token.length() > 5;
    }
    public static void main(String[] args) {
        TokenValidator validator = new TokenValidator();
        System.out.println("验证结果 (应为true): " + validator.validateAccessToken("abc123"));
        System.out.println("验证结果 (应为false): " + validator.validateAccessToken("abc"));
        System.out.println("验证结果 (应为false): " + validator.validateAccessToken(null));
    }
}

请编写一个Java方法，用于验证用户的访问令牌是否有效。该方法首先需要检查令牌的格式是否正确，然后需要与数据库中存储的令牌进行比较。如果令牌格式正确且与数据库中的令牌匹配，则返回true，否则返回false。请确保你的代码能够处理可能的异常，并且在数据库查询中使用了模拟的数据。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.Optional;
public class TokenValidator {
    public Boolean validateAccessToken(String accessToken) {
    }
    private boolean isTokenFormatValid(String token) {
    }
}
```

import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertTrue;
import org.junit.jupiter.api.Test;
public class TokenValidatorTest {
    @Test
    public void testValidateAccessToken_ValidToken() {
        TokenValidator validator = new TokenValidator();
        assertTrue(validator.validateAccessToken("abc123"));
    }
    @Test
    public void testValidateAccessToken_InvalidToken_ShortLength() {
        TokenValidator validator = new TokenValidator();
        assertFalse(validator.validateAccessToken("abc"));
    }
    @Test
    public void testValidateAccessToken_InvalidToken_Null() {
        TokenValidator validator = new TokenValidator();
        assertFalse(validator.validateAccessToken(null));
    }
    @Test
    public void testValidateAccessToken_InvalidToken_WrongToken() {
        TokenValidator validator = new TokenValidator();
        assertFalse(validator.validateAccessToken("wrongToken"));
    }
    @Test
    public void testValidateAccessToken_InvalidToken_EmptyString() {
        TokenValidator validator = new TokenValidator();
        assertFalse(validator.validateAccessToken(""));
    }
}


public class ParkingAssistant {
    public void autoStop(double distance) {
        if (distance <= 10.0) {
            System.out.println("停车成功");
        } else {
            System.out.println("继续行驶");
        }
    }
    public static void main(String[] args) {
        ParkingAssistant assistant = new ParkingAssistant();
        assistant.autoStop(5);
        assistant.autoStop(15);
        assistant.autoStop(10);
    }
}

请编写一个Java程序，实现一个简单的停车辅助系统。当车辆接近障碍物至少10米时，系统应自动停止车辆。你需要完成以下任务：

- 定义一个名为`ParkingAssistant`的类。
- 在该类中，实现一个名为`autoStop`的方法，该方法接收一个参数表示车辆与障碍物的距离（单位：米）。
- 如果距离小于或等于10米，方法应打印出"停车成功"，表示车辆已停止。
- 否则，打印出"继续行驶"，表示车辆可以安全行驶。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
public class ParkingAssistant {
    public void autoStop(double distance) {
    }
}
```

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
import java.io.ByteArrayOutputStream;
import java.io.PrintStream;
public class ParkingAssistantTest {
    @Test
    public void testAutoStopWhenDistanceEqualToFive() {
        ParkingAssistant assistant = new ParkingAssistant();
        ByteArrayOutputStream outContent = new ByteArrayOutputStream();
        System.setOut(new PrintStream(outContent));
        assistant.autoStop(5);
        assertTrue(outContent.toString().contains("停车成功"));
    }
    @Test
    public void testAutoStopWhenDistanceEqualToFifteen() {
        ParkingAssistant assistant = new ParkingAssistant();
        ByteArrayOutputStream outContent = new ByteArrayOutputStream();
        System.setOut(new PrintStream(outContent));
        assistant.autoStop(15);
        assertTrue(outContent.toString().contains("继续行驶"));
    }
    @Test
    public void testAutoStopWhenDistanceEqualToTen() {
        ParkingAssistant assistant = new ParkingAssistant();
        ByteArrayOutputStream outContent = new ByteArrayOutputStream();
        System.setOut(new PrintStream(outContent));
        assistant.autoStop(10);
        assertTrue(outContent.toString().contains("停车成功"));
    }
    @Test
    public void testAutoStopWhenDistanceLessThanTen() {
        ParkingAssistant assistant = new ParkingAssistant();
        ByteArrayOutputStream outContent = new ByteArrayOutputStream();
        System.setOut(new PrintStream(outContent));
        assistant.autoStop(7.5);
        assertTrue(outContent.toString().contains("停车成功"));
    }
    @Test
    public void testAutoStopWhenDistanceGreaterThanTen() {
        ParkingAssistant assistant = new ParkingAssistant();
        ByteArrayOutputStream outContent = new ByteArrayOutputStream();
        System.setOut(new PrintStream(outContent));
        assistant.autoStop(12.5);
        assertTrue(outContent.toString().contains("继续行驶"));
    }
}


import java.util.Objects;
import java.util.Optional;
class Book {
    private String title;
    private Optional<String> audiobook;
    public Book(String title, Optional<String> audiobook) {
        this.title = title;
        this.audiobook = audiobook;
    }
    public Optional<String> getAudiobook() {
        return audiobook;
    }
}
class AudiobookChecker {
    public void checkAudiobook(Book book, Optional<String> expectedAudiobook) throws AudiobookMismatchException {
        if (!Objects.equals(book.getAudiobook(), expectedAudiobook)) {
            throw new AudiobookMismatchException("有声书版本不匹配");
        }
    }
}
class AudiobookMismatchException extends Exception {
    public AudiobookMismatchException(String message) {
        super(message);
    }
}
public class AudiobookCheckDemo {
    public static void main(String[] args) {
        Book book1 = new Book("Java Programming", Optional.of("Java Programming Audiobook"));
        Book book2 = new Book("Python Programming", Optional.empty());
        AudiobookChecker checker = new AudiobookChecker();
        try {
            checker.checkAudiobook(book1, Optional.of("Java Programming Audiobook"));
            System.out.println("书籍1有声书版本检查通过");
        } catch (AudiobookMismatchException e) {
            System.out.println(e.getMessage());
        }
        try {
            checker.checkAudiobook(book2, Optional.empty());
            System.out.println("书籍2有声书版本检查通过");
        } catch (AudiobookMismatchException e) {
            System.out.println(e.getMessage());
        }
        try {
            checker.checkAudiobook(book1, Optional.of("错误的有声书版本"));
        } catch (AudiobookMismatchException e) {
            System.out.println("书籍1有声书版本检查未通过: " + e.getMessage());
        }
    }
}

假设你正在开发一个图书管理系统，需要实现一个功能来检查某本书是否有有声书版本。请编写一个方法，该方法接收一个书籍对象和一个有声书版本的可选信息，如果书籍对象中的有声书信息与提供的信息不匹配，抛出一个自定义异常。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.Objects;
import java.util.Optional;
class Book {
    private String title;
    private Optional<String> audiobook;
    public Book(String title, Optional<String> audiobook) {
    }
    public Optional<String> getAudiobook() {
        return null;
    }
}
class AudiobookChecker {
    public void checkAudiobook(Book book, Optional<String> expectedAudiobook) throws AudiobookMismatchException {
    }
}
class AudiobookMismatchException extends Exception {
    public AudiobookMismatchException(String message) {
    }
}
```

import java.util.Optional;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
class BookTest {
    @Test
    void testGetAudiobook() {
        Book bookWithAudiobook = new Book("Java Programming", Optional.of("Java Programming Audiobook"));
        assertEquals(Optional.of("Java Programming Audiobook"), bookWithAudiobook.getAudiobook());
        Book bookWithoutAudiobook = new Book("Python Programming", Optional.empty());
        assertEquals(Optional.empty(), bookWithoutAudiobook.getAudiobook());
    }
}
class AudiobookCheckerTest {
    @Test
    void testCheckAudiobookMatch() throws AudiobookMismatchException {
        Book book = new Book("Java Programming", Optional.of("Java Programming Audiobook"));
        AudiobookChecker checker = new AudiobookChecker();
        checker.checkAudiobook(book, Optional.of("Java Programming Audiobook"));
    }
    @Test
    void testCheckAudiobookMismatch() {
        Book book = new Book("Java Programming", Optional.of("Java Programming Audiobook"));
        AudiobookChecker checker = new AudiobookChecker();
        assertThrows(AudiobookMismatchException.class, () -> {
            checker.checkAudiobook(book, Optional.of("Wrong Audiobook"));
        });
    }
    @Test
    void testCheckAudiobookEmptyMatch() throws AudiobookMismatchException {
        Book book = new Book("Python Programming", Optional.empty());
        AudiobookChecker checker = new AudiobookChecker();
        checker.checkAudiobook(book, Optional.empty());
    }
    @Test
    void testCheckAudiobookEmptyMismatch() {
        Book book = new Book("Python Programming", Optional.empty());
        AudiobookChecker checker = new AudiobookChecker();
        assertThrows(AudiobookMismatchException.class, () -> {
            checker.checkAudiobook(book, Optional.of("Some Audiobook"));
        });
    }
}


import java.util.Objects;
class StudentScore {
    private int studentId;
    private String studentName;
    private int mathScore;
    private int englishScore;
    private int scienceScore;
    public StudentScore(int studentId, String studentName, int mathScore, int englishScore, int scienceScore) {
        this.studentId = studentId;
        this.studentName = studentName;
        this.mathScore = mathScore;
        this.englishScore = englishScore;
        this.scienceScore = scienceScore;
    }
    @Override
    public String toString() {
        return "StudentScore{" +
                "studentId=" + studentId +
                ", studentName='" + studentName + '\'' +
                ", mathScore=" + mathScore +
                ", englishScore=" + englishScore +
                ", scienceScore=" + scienceScore +
                '}';
    }
}
public class ScoreProcessor {
    public StudentScore generateStudentScore(Object[] objectArray) {
        int studentId = Integer.parseInt(String.valueOf(objectArray[0]));
        String studentName = String.valueOf(objectArray[1]);
        int mathScore = Integer.parseInt(String.valueOf(objectArray[2]));
        int englishScore = Integer.parseInt(String.valueOf(objectArray[3]));
        int scienceScore = Integer.parseInt(String.valueOf(objectArray[4]));
        return new StudentScore(studentId, studentName, mathScore, englishScore, scienceScore);
    }
    public static void main(String[] args) {
        ScoreProcessor processor = new ScoreProcessor();
        Object[] data = {1, "张三", "90", "85", "88"};
        StudentScore score = processor.generateStudentScore(data);
        System.out.println(score);
    }
}

请编写一个Java程序，用于处理学生的成绩信息。给定一个对象数组，每个对象代表一个学生的不同成绩信息，包括学生的ID、姓名、数学成绩、英语成绩、科学成绩等。你需要将这些信息封装到一个学生成绩对象中，并返回这个对象。请确保你的程序能够处理不同的数据类型，例如，数学成绩可能以字符串形式给出，需要转换为整型。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.Objects;
class StudentScore {
    private int studentId;
    private String studentName;
    private int mathScore;
    private int englishScore;
    private int scienceScore;
    public StudentScore(int studentId, String studentName, int mathScore, int englishScore, int scienceScore) {
    }
    @Override
    public String toString() {
    }
}
public class ScoreProcessor {
    public StudentScore generateStudentScore(Object[] objectArray) {
    }
}
```

import org.junit.Test;
import static org.junit.Assert.*;
public class ScoreProcessorTest {
    @Test(expected = ArrayIndexOutOfBoundsException.class)
    public void testGenerateStudentScoreWithEmptyArray() {
        ScoreProcessor processor = new ScoreProcessor();
        Object[] emptyArray = {};
        processor.generateStudentScore(emptyArray);
    }
    @Test(expected = NumberFormatException.class)
    public void testGenerateStudentScoreWithInvalidDataType() {
        ScoreProcessor processor = new ScoreProcessor();
        Object[] invalidDataArray = {1, "张三", "NotANumber", "85", "88"};
        processor.generateStudentScore(invalidDataArray);
    }
    @Test
    public void testGenerateStudentScoreWithValidData(){
        ScoreProcessor processor = new ScoreProcessor();
        Object[] data = {1, "张三", "90", "85", "88"};
        StudentScore expected = new StudentScore(1, "张三", 90, 85, 88);
        StudentScore actual = processor.generateStudentScore(data);
        assertEquals(expected.toString(), actual.toString());
    }
    @Test
    public void testGenerateStudentScoreWithNegativeScores() {
        ScoreProcessor processor = new ScoreProcessor();
        Object[] data = {2, "李四", "-10", "85", "88"};
        StudentScore expected = new StudentScore(2, "李四", -10, 85, 88);
        StudentScore actual = processor.generateStudentScore(data);
        assertEquals(expected.toString(), actual.toString());
    }
    @Test
    public void testGenerateStudentScoreWithEmptyName() {
        ScoreProcessor processor = new ScoreProcessor();
        Object[] data = {3, "", "50", "75", "90"};
        StudentScore expected = new StudentScore(3, "", 50, 75, 90);
        StudentScore actual = processor.generateStudentScore(data);
        assertEquals(expected.toString(), actual.toString());
    }
}


import java.util.Scanner;
public class SimpleCalculator {
    public double add(double a, double b) {
        return a + b;
    }
    public double subtract(double a, double b) {
        return a - b;
    }
    public double multiply(double a, double b) {
        return a * b;
    }
    public double divide(double a, double b) {
        if (b == 0) {
            System.out.println("错误：除数不能为0。");
            return 0;
        }
        return a / b;
    }
    public static void main(String[] args) {
        SimpleCalculator calculator = new SimpleCalculator();
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入两个数字和一个操作符（+、-、*、/），例如：3 + 4");
        double num1 = scanner.nextDouble();
        String operator = scanner.next();
        double num2 = scanner.nextDouble();
        switch (operator) {
            case "+":
                System.out.println("结果是：" + calculator.add(num1, num2));
                break;
            case "-":
                System.out.println("结果是：" + calculator.subtract(num1, num2));
                break;
            case "*":
                System.out.println("结果是：" + calculator.multiply(num1, num2));
                break;
            case "/":
                System.out.println("结果是：" + calculator.divide(num1, num2));
                break;
            default:
                System.out.println("未知的操作符：" + operator);
                break;
        }
    }
}

请编写一个Java程序，实现一个简单的计算器类`SimpleCalculator`。这个类应该能够执行基本的算术运算：加法、减法、乘法和除法。请确保你的实现能够处理除以零的情况，并在这种情况下打印一条友好的错误消息，而不是让程序崩溃。确保你的代码易于理解，变量命名合理，并包含必要的注释。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.Scanner;
public class SimpleCalculator {
    public double add(double a, double b) {
    }
    public double subtract(double a, double b) {
    }
    public double multiply(double a, double b) {
    }
    public double divide(double a, double b) {
    }
}
```

import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
public class SimpleCalculatorTest {
    private SimpleCalculator calculator;
    @BeforeEach
    public void setUp() {
        calculator = new SimpleCalculator();
    }
    @Test
    public void testAdd() {
        double result = calculator.add(2, 3);
        assertEquals(5, result, 0.001);
    }
    @Test
    public void testSubtract() {
        double result = calculator.subtract(5, 3);
        assertEquals(2, result, 0.001);
    }
    @Test
    public void testMultiply() {
        double result = calculator.multiply(4, 3);
        assertEquals(12, result, 0.001);
    }
    @Test
    public void testDivide() {
        double result = calculator.divide(6, 3);
        assertEquals(2, result, 0.001);
    }
    @Test
    public void testDivideByZero() {
        double result = calculator.divide(6, 0);
        assertEquals(0, result, 0.001);
    }
}


import java.util.HashMap;
import java.util.Map;
public class HealthAdvice {
    public static String getHealthAdvice(int age) {
        if (age < 12) {
            return "多喝水";
        } else if (age >= 12 && age <= 18) {
            return "保持适当的运动";
        } else if (age >= 19 && age <= 40) {
            return "保持健康饮食";
        } else if (age >= 41 && age <= 60) {
            return "定期体检";
        } else {
            return "保持积极的生活态度";
        }
    }
    public static void checkHealthAdvice() {
        Map<Integer, String> testCases = new HashMap<>();
        testCases.put(5, "多喝水");
        testCases.put(15, "保持适当的运动");
        testCases.put(30, "保持健康饮食");
        testCases.put(50, "定期体检");
        testCases.put(70, "保持积极的生活态度");
        boolean isCorrect = true;
        for (Map.Entry<Integer, String> entry : testCases.entrySet()) {
            String advice = getHealthAdvice(entry.getKey());
            if (!advice.equals(entry.getValue())) {
                isCorrect = false;
                System.out.println("错误: 对于年龄 " + entry.getKey() + " 的建议应该是 '" + entry.getValue() + "'，但你的方法返回了 '" + advice + "'");
            }
        }
        if (isCorrect) {
            System.out.println("所有测试用例都通过了！");
        }
    }
    public static void main(String[] args) {
        checkHealthAdvice();
    }
}

请编写一个Java方法，该方法根据用户的年龄返回相应的健康建议。具体要求如下：

- 如果用户年龄小于12岁，建议"多喝水"。
- 如果用户年龄在12岁到18岁之间（包括12岁和18岁），建议"保持适当的运动"。
- 如果用户年龄在19岁到40岁之间（包括19岁和40岁），建议"保持健康饮食"。
- 如果用户年龄在41岁到60岁之间（包括41岁和60岁），建议"定期体检"。
- 如果用户年龄超过60岁，建议"保持积极的生活态度"。
请用Java实现不包含Main函数的完整代码，并遵循如下类型定义：

```java
import java.util.HashMap;
import java.util.Map;
public class HealthAdvice {
    public static String getHealthAdvice(int age) {
    }
    public static void checkHealthAdvice() {
    }
}
```

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
public class HealthAdviceTest {
    @Test
    public void testGetHealthAdviceUnder12() {
        assertEquals("多喝水", HealthAdvice.getHealthAdvice(5));
    }
    @Test
    public void testGetHealthAdviceBetween12And18() {
        assertEquals("保持适当的运动", HealthAdvice.getHealthAdvice(15));
    }
    @Test
    public void testGetHealthAdviceBetween19And40() {
        assertEquals("保持健康饮食", HealthAdvice.getHealthAdvice(30));
    }
    @Test
    public void testGetHealthAdviceBetween41And60() {
        assertEquals("定期体检", HealthAdvice.getHealthAdvice(50));
    }
    @Test
    public void testGetHealthAdviceAbove60() {
        assertEquals("保持积极的生活态度", HealthAdvice.getHealthAdvice(70));
    }
}